small refactor to make it testable.

src/state/CallViewModel/remoteMembers/LivekitParticipantIdentity.ts

@@ -0,0 +1,53 @@
+/*
+Copyright 2025 New Vector Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+import { encodeUnpaddedBase64Url } from "matrix-js-sdk";
+import { sha256 } from "matrix-js-sdk/lib/digest";
+import { type CallMembershipIdentityParts } from "matrix-js-sdk/lib/matrixrtc/EncryptionManager";
+import { from, type Observable } from "rxjs";
+
+const livekitParticipantIdentityCache = new Map<string, string>();
+
+/**
+ * The string that is computed based on the membership and used for the computing the hash.
+ * `${userId}:${deviceId}:${membershipID}`
+ * as the direct imput for: await sha256(input)
+ */
+export const livekitIdentityInput = ({
+  userId,
+  deviceId,
+  memberId,
+}: CallMembershipIdentityParts): string => `${userId}|${deviceId}|${memberId}`;
+
+export function computeLivekitParticipantIdentity$(
+  membership: CallMembershipIdentityParts,
+  kind: "rtc" | "session",
+): Observable<string> {
+  const compute = async (): Promise<string> => {
+    switch (kind) {
+      case "rtc": {
+        const input = livekitIdentityInput(membership);
+        if (livekitParticipantIdentityCache.size > 400)
+          // prevent memory leaks in a stupid/simple way
+          livekitParticipantIdentityCache.clear();
+        // TODO use non deprecated memberId
+        if (livekitParticipantIdentityCache.has(input))
+          return livekitParticipantIdentityCache.get(input)!;
+        else {
+          const hashBuffer = await sha256(input);
+          const hashedString = encodeUnpaddedBase64Url(hashBuffer);
+          livekitParticipantIdentityCache.set(input, hashedString);
+          return hashedString;
+        }
+      }
+      case "session":
+      default:
+        return `${membership.userId}:${membership.deviceId}`;
+    }
+  };
+  return from(compute());
+}

src/state/CallViewModel/remoteMembers/MatrixLivekitMembers.test.ts

@@ -28,7 +28,6 @@ import {
   flushPromises,
   mockCallMembership,
   mockRemoteParticipant,
-  withTestScheduler,
 } from "../../../utils/test.ts";
 import { type Connection } from "./Connection.ts";
 import { constant } from "../../Behavior.ts";

src/state/CallViewModel/remoteMembers/MatrixLivekitMembers.ts

@@ -15,15 +15,13 @@ import {
 } from "matrix-js-sdk/lib/matrixrtc";
 import { combineLatest, filter, map, switchMap } from "rxjs";
 import { logger as rootLogger } from "matrix-js-sdk/lib/logger";
-import { sha256 } from "matrix-js-sdk/lib/digest";
-import { encodeUnpaddedBase64Url } from "matrix-js-sdk";
-import { type CallMembershipIdentityParts } from "matrix-js-sdk/lib/matrixrtc/EncryptionManager";
 
 import { type Behavior } from "../../Behavior";
 import { type IConnectionManager } from "./ConnectionManager";
 import { Epoch, type ObservableScope } from "../../ObservableScope";
 import { type Connection } from "./Connection";
 import { generateItemsWithEpoch } from "../../../utils/observable";
+import { computeLivekitParticipantIdentity$ } from "./LivekitParticipantIdentity";
 
 const logger = rootLogger.getChild("[MatrixLivekitMembers]");
 
@@ -73,25 +71,28 @@ export function createMatrixLivekitMembers$({
    */
   const membershipsWithTransportAndLivekitIdentity$ =
     membershipsWithTransport$.pipe(
-      switchMap(async (membershipsWithTransport) => {
+      switchMap((membershipsWithTransport) => {
         const { value, epoch } = membershipsWithTransport;
         const membershipsWithTransportAndLkIdentityPromises = value.map(
-          async (obj) => {
-            return computeLivekitParticipantIdentity(
+          (obj) => {
+            return computeLivekitParticipantIdentity$(
               obj.membership,
               obj.membership.kind,
             );
           },
         );
-        const identities = await Promise.all(
+        return combineLatest(
           membershipsWithTransportAndLkIdentityPromises,
+        ).pipe(
+          map((identities) => {
+            const membershipsWithTransportAndLkIdentity = value.map(
+              ({ transport, membership }, index) => {
+                return { transport, membership, identity: identities[index] };
+              },
+            );
+            return new Epoch(membershipsWithTransportAndLkIdentity, epoch);
+          }),
         );
-        const membershipsWithTransportAndLkIdentity = value.map(
-          ({ transport, membership }, index) => {
-            return { transport, membership, identity: identities[index] };
-          },
-        );
-        return new Epoch(membershipsWithTransportAndLkIdentity, epoch);
       }),
     );
 
@@ -164,42 +165,3 @@ export function areLivekitTransportsEqual(
   if (!t1 && !t2) return true;
   return false;
 }
-
-const livekitParticipantIdentityCache = new Map<string, string>();
-
-/**
- * The string that is computed based on the membership and used for the computing the hash.
- * `${userId}:${deviceId}:${membershipID}`
- * as the direct imput for: await sha256(input)
- */
-export const livekitIdentityInput = ({
-  userId,
-  deviceId,
-  memberId,
-}: CallMembershipIdentityParts): string => `${userId}|${deviceId}|${memberId}`;
-
-export async function computeLivekitParticipantIdentity(
-  membership: CallMembershipIdentityParts,
-  kind: "rtc" | "session",
-): Promise<string> {
-  switch (kind) {
-    case "rtc": {
-      const input = livekitIdentityInput(membership);
-      if (livekitParticipantIdentityCache.size > 400)
-        // prevent memory leaks in a stupid/simple way
-        livekitParticipantIdentityCache.clear();
-      // TODO use non deprecated memberId
-      if (livekitParticipantIdentityCache.has(input))
-        return livekitParticipantIdentityCache.get(input)!;
-      else {
-        const hashBuffer = await sha256(input);
-        const hashedString = encodeUnpaddedBase64Url(hashBuffer);
-        livekitParticipantIdentityCache.set(input, hashedString);
-        return hashedString;
-      }
-    }
-    case "session":
-    default:
-      return `${membership.userId}:${membership.deviceId}`;
-  }
-}

src/state/CallViewModel/remoteMembers/integration.test.ts

@@ -22,6 +22,7 @@ import { ECConnectionFactory } from "./ConnectionFactory.ts";
 import { type OpenIDClientParts } from "../../../livekit/openIDSFU.ts";
 import {
   mockCallMembership,
+  mockComputeLivekitParticipantIdentity$,
   mockMediaDevices,
   withTestScheduler,
 } from "../../../utils/test.ts";
@@ -43,6 +44,11 @@ let lkRoomFactory: () => LivekitRoom;
 
 const createdMockLivekitRooms: Map<string, LivekitRoom> = new Map();
 
+vi.mock(import("./LivekitParticipantIdentity.ts"), async (importOriginal) => ({
+  ...(await importOriginal()),
+  computeLivekitParticipantIdentity$: mockComputeLivekitParticipantIdentity$,
+}));
+
 beforeEach(() => {
   testScope = new ObservableScope();
   mockClient = {